CA125, a large transmembrane mucin (MUC16), heavily glycosylated with both N- and O-linked glycans, is approved for monitoring EOC progression and therapeutic response3,4 but has a low diagnostic specificity because elevated levels of CA125 are frequently increased in several benign gynecological conditions and in non-gynecologic cancers, like pancreatic and lung cancer5. Here, MUC16 is linked to female reproductive organ cancer.